What Does a Coronavirus Test Detect in Humans?

Coronavirus tests are crucial tools for diagnosing infections caused by SARS-CoV-2, the virus responsible for COVID-19. These tests detect the presence of the virus or the body's response to it through different methodologies, primarily focusing on viral RNA, viral antigens, and antibodies produced by the immune system.

Table of Contents

1. Detection Methods
2. Viral RNA Detection
3. Antigen Detection
4. Antibody Detection
5. Company Solutions
6. References

Detection Methods

Three primary types of tests are used to detect Coronavirus in humans:

• Viral RNA Detection (RT-PCR)
• Antigen Detection
• Antibody Detection

Viral RNA Detection

RT-PCR (Reverse Transcription Polymerase Chain Reaction) tests are considered the gold standard for detecting active infections. They identify the presence of viral RNA in a sample, usually taken from the respiratory tract. RT-PCR tests are highly sensitive and specific, with their parameters including:

• Sensitivity: Approximately 95-100%
• Specificity: Approximately 98-100%
• Turnaround Time: Typically 12-24 hours

Antigen Detection

Antigen tests detect specific proteins on the surface of the virus. These tests are usually faster but less sensitive than RT-PCR tests. They are valuable for rapid screening, especially in high-prevalence settings. Key parameters include:

• Sensitivity: Ranges from 50-90%
• Specificity: Often above 95%
• Turnaround Time: Typically 15-30 minutes

Antibody Detection

Antibody tests assess the presence of antibodies in the blood, indicating a past infection or response to vaccination. These tests are not for diagnosing active infections but help in understanding immune response and epidemiological studies. Their parameters include:

• Sensitivity: Varies widely, 80-99% depending on time since infection
• Specificity: Generally over 95%
• Use Case: Typically used 1-3 weeks post-infection or vaccination

Company Solutions

• Roche Diagnostics: Provides RT-PCR tests with high throughput capabilities, catering to large-scale testing.
• Abbott Laboratories: Offers rapid antigen tests, such as BinaxNOW, designed for quick results.
• Bio-Rad Laboratories: Specializes in antibody test kits for both research and diagnostic purposes.
• Thermo Fisher Scientific: Supplies comprehensive RNA extraction kits and RT-PCR equipment.
• Siemens Healthineers: Develops both antigen and antibody tests for comprehensive diagnostic solutions.

References

1. U.S. Centers for Disease Control and Prevention (CDC). COVID-19 Testing: What You Need to Know. Available at: [CDC Website]
2. World Health Organization (WHO). Diagnostic testing for SARS-CoV-2. June 2020. Available at: [WHO Website]
3. Johns Hopkins University. Understanding Antibody Tests for COVID-19. Available at: [JHU Website]
4. Nature Journal. Diagnostics for SARS-CoV-2 infections. April 2020. DOI: [10.1038/s41577-020-00461-8]
5. Journal of Clinical Virology. Comparative accuracy of antibody and antigen tests. DOI: [10.1016/j.jcv.2021.104895]